This invention relates to contact elements, or terminals, which are inserted in electrical connectors to provide the electrically-conducting elements which are brought into engagement with complementary electrically-conducting elements when the connector mating portions are brought into mated position. The invention is primarily, although not exclusively, concerned with improved terminals for connectors of the low, or zero, insertion force type. Such connectors generally work on the principle of bringing the opposed terminal elements into overlying but nonengaging position as the connector portions are moved together, and thereafter causing relative transverse movement of the opposed terminal elements to bring them into engagement with one another.
As set forth in Hollingsead and Pryor Application Ser. No. 535,307, filed Dec. 23, 1974, and assigned to the assignee of this application, numerous prior art patents have dealt with the problem of providing the most satisfactory terminal, or electrical contact, elements for electrical connectors, printed circuit boards, and the like. Reference to that application will provide a list of patents supplied both by the applicant and by the Patent Office.
The state of relevant art, insofar as the present applicant is aware, is well represented by the terminal element structures shown in the following patents: Mishelevich et al U.S. Pat. No. 3,145,067; Walkup U.S. Pat. No. 3,683,317; Schneck U.S. Pat. No. 3,351,891; Anhalt U.S. Pat. No. 3,587,037; Pistey U.S. Pat. No. 3,324,447; Krehbiel U.S. Pat. No. 2,938,190; Greco et al U.S. Pat. No. 3,160,459; and Collier et al U.S. Pat. No. 3,880,488.
Some of the attributes required by terminal elements for electrical connectors, which are present in the invention herein set forth as well as the prior art are: ease of insertion, automatic locking in place, good retention along with simple removability when required, interchangeability in use in either the male or female portion of the connector, and strength combined with sufficient resilience to insure effective electrical contact by permitting resilient deflection in engaging, or contact, position.
Some of the attributes possessed by the present invention, which are believed to constitute benefits not provided as well by the prior art are:
A. Reduction to a minimum of air space around the terminal element after it has been installed in the passage, or channel, in the insulating support member. One of the significant problems encountered in electrical connectors is loss of electrical conducting efficiency due to corrosion and similar difficulties. These difficulties are caused in part by contaminants carried by the air which reaches the terminal elements and their contact points. The forced air cooling often provided for electronic modular units and other electronic components greatly accelerates this corrosion process if substantial amounts of air move through the connector passages in which the terminal elements are mounted.
b. Unusually good support for the terminal element in the insulating support member. This invention provides a terminal element structure which has a particularly well-supported engagement with the walls of the passage into which the terminal element is inserted.
c. Reduced likelihood of failure or dislodging of the terminal element, an advantage provided by a redundancy concept which involves duplicating the electrical conducting path and duplicating the means for locking, or retaining, the terminal element in its channel, or passage; so that breakage of one of the redundant portions of the terminal element will not destroy its functional effectiveness.
d. Manufacturing simplicity and process-conscious design which permits the terminal elements to be made by a series of automatically controlled press-forming, or stamping, steps. The structure is such that it can be manufactured in a series of press forming stations, starting with a punch press into which a metal ribbon is fed. This manufacturing simplicity permits the use of a process which is both reliable and cost effective.
e. Insertion and extraction simplicity, including specific advantages, such as positive prevention of accidental insertion of the terminal element upside down, and reduced tendency of the terminal element, when it is being removed, to tear the rubber seal associated with the opening into the back of the connector shell through which the electrical wires pass.
f. Better design for the connection of an electric wire to the outer end of the connector, including means for assisting in properly positioning the end of the wire prior to crimping the terminal element flanges into wire-gripping position.